The invention refers to a filter apparatus, particularly for a device for extruding thermoplastic synthetic plastics material, comprising a housing having at least one inlet passage being in connection with an inlet opening for the supply of the material to be filtered and having at least one outlet passage being in connection with an outlet opening for discharging the filtered material and having slideably arranged therein at least two carrier members, each of which carries a sieve means through which in operating position of the carrier member the material to be filtered passes from the inlet side, which is connected to the inlet passage, of the sieve means to the outlet side opening into the outlet passage.
In particular when producing thin-walled articles of thermoplastic synthetic plastics material, the melt of synthetic plastics material expelled by the extruder must be filtered for obtaining a perfect product. As a rule, filtering is effected by means of a perforated plate arranged between the extruder screw and the extruder nozzle and by means of a sieve arrangement arranged in front of the perforated plate as seen in flow direction of the extruded melt of synthetic plastics material.
When recycling waste of synthetic plastics material in the extruder it is necessary due to the higher contamination content, to clean and/or to interchange the contaminated sieve arrangement during the extrusion process. Various devices are known for this purpose.